The invention relates to an analog current switch in bipolar technology in which the switching circuit comprises a switching diode and an intermediate isolating transistor whose emitter is connected to a current source and whose collector is connected to the anode of said switching diode, the emitter of said intermediate transistor, the anode and the cathode of said switching diode, respectively, constituting the signal input, the switching signal input and the signal output of said switch. The switching signal either turns on said switching diode, in which case the current injected into said intermediate transistor by said source is transferred towards said signal output, or turns off said switching diode, in which case the current is applied to said switching-signal input.
Such a switching circuit is known from British Patent Specification No. 1,379,591, in which circuit the intermediate transistor with a low output capacitance is employed for isolating the current source from the switching diode and thereby reducing the stray capacitance of the device. In addition, for biassing said transistor it is necessary to apply a fixed potential to its base, which potential is supplied by an external voltage source.